Reviews by patients who have Tooth Pain and take Zinc either as part of daily diet or as method of treatment. Positive and negative experiences from patients with Tooth Pain that take Zinc
1 Red or black colored stool may be a sign of bleeding in the GI tract (from the esophagus, stomach, small intestine or colon) and should not be ignored.  When stool color changes, what tests need to be done depend upon depends upon what cause is suspected for the stool color change.
Black: Black stool is a surprisingly common side effect and can be caused from anything from a night of binging on black licorice and Guinness, to your iron supplement regimen, to ingesting large amounts of bismuth subsalicylate aka Pepto-Bismol.